Switch



Nov. 12, 1929. c. F. calLczr-mls-r 1,735,112

SWITCH Filed Feb. 26, 1921 1 N V EN TOR. g/a/mc'e F 6 /'/6/7 r/Jf \ATTORNEY Patented Nov. 12, 1929 UNI ED STATES PATENT OFFICE- CLARENCE F. GILCHRIST, OF TOLEDO, OHIO, ASSIGNOR, BY MESNE ASSIGNMENTS, TO THE ELECTRIC AUTO-LITE COMPANY, OF TOLEDO, OHIO, A CORPORATION OF OHIO SWITCH Application filed February 26, 1921. Serial No. 448,094.

This invention relates to switches, particularly to pedal switches such as are used to Control electric motors for automobile engines and it is an object of the invention to provide a switch for this purpose which shall be simple, strong and durable and adapted to be manufactured in large quantities at a minimum expense.

A structure constituting an embodiment of my invention is illustrated in the accompanying drawings, forming a part hereof, in which:

Figure I is a top plan view of a switch constructed in accordance with my invention;

Fig. II is a bottom plan view of the same;

Fig. III is a vertical sectional view taken on the line IIIIII of Fig. I;

Fig. IV is a vertical sectional view taken on the line IVIV of Fig. II.

Fig. V is a fragmentary view similar to Fig. III with the switch blade depressed;

Fig. V1 is a perspective view of a part of the casing or frame of the switch, and

Fig. VII is a fragmentary view showing a detai In the drawings, the same reference numerals refer to similar parts through the several views, and the sectional views are taken looking in the direction of the arrows at the ,ends of the section lines.

Referring to the drawings, a rectangular casing or frame 5 is formed up from a sheet metal blank by bending up the four sides which are held in proper relative position by ears 6 integral with the end walls of the casing. The two side walls have triangularshaped ears or flanges 7 extending outwardly from their upper portions and the two end walls have smaller flanges or ears 8 which also extend outwardly from their upper portions. The casing is completed by a cover member 10 which is shown as hexagonal in shape and as having a narrow downwardly extending flange 11 about its periphery within which the ears or flanges 7 and 8 of the casing member fit. At two opposite sides of the cover a portion of the flange 11 is bent inwardly as shown at 12, firmly engaging the flanges 8 of the casing. The complete casing is adapted to be secured to the floor board 14 of an automobile by means of two bolts 15 having hexagon nuts 16, which bolts and nuts are so positioned by the openings 17 and 18 in the flanges 7 and the cover 10, respectively, and that the flange 11 of the cover co-operates with the nuts '16 to prevent them from rotating. A tube 20 is secured to the cover plate 10 as, for example, by means of integral ears 21 as shown in Fi 6 and extends upwardly through the floor Eoard 14 to guide and protect the plunger 22 with its return spring 38 and cap 39. I

Secured to the bottom of the casing and extending through the openings 25 there is a pair of heavy terminal contact members 26 having rectangular-shaped heads and threaded shanks for receiving nuts 29 by which external circuit connections may be made. The upper or contact faces of these terminal members are slightly beveled or inclined as shown in Fig. III for a purpose to be described hereinafter. The head portions 27 are also provided with small teats 30 on the under side which engage in suitable openings in the insulation 32 for the purpose of preventing displacement of the terminal members; The strip of insulation 32 fits within the casing between the end walls and between the casing bottom and the heads 27 to insulate the same from the casing and this strip also extends up each side wall as clearly shown in Fig. IV. The openings 25 in the casing are concentric and substantially larger than the corresponding openings in the in sulation 32. Underneath the bottom of the casing 5 a second strip of insulation is provided to insulate the terminal members 26 from the casing and this insulating strip has an intermediate portion bent back upon itself and extending outwardly to form a shield 36 midway between the two terminals. By reason of this construction, the liability of producing a short circuit when the connecting wires are being attached is greatly lessened.

The plunger 22 comprises a central rod 38 having a cap 39 and a coil spring 40. A contact bridging member or blade 42 is loosely carried by and insulated from the lower end of the rod 38 by suitable washers, the end of the rod being riveted over against a metallic washer 43 while a suitable opening 44 is provided in the insulation 32 to receive the end of the rod. The blade 42 is guided in its downward movement by the upturned portions of the insulation 32 and is also efiectively insulated thereby from'the walls of the cas ing. By reason of the bevel on the upper faces of the terminal members 26 the blade 42 in its minal members and as more pressure is exert-- ed upon the plunger the blade bends slightly to contact with the flat faces of the terminals. Before the push rod can be depressed to such an extent that the blade would be so bent that it en aged only the inner edges of theterminzfmembers, the washer 43 on the push rod engages the insulation 32, the parts being so proportioned thatunder no possibility can the push rod be depressed beyond the point where the blade has extended surface contact with with the terminal members 26;

Inasmuch as the invention herein disclosed is susceptible of various other embodiments and as various changes might be made in the embodiment set forth, it is to be understood that all matter described above or shown in the accompanying drawing is to be interpreted as illustrative only, and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. A switch for an automobile electric starter comprising a casing; a pair of-"spaced stationary contact members secured to the bottom thereof; va plunger mounted in the top of said casing movable toward said contact members; a single flat strip of conducting material having straight ends and being loosely carried at its center by said plunger for bridging said contact members when said plunger is moved, the contact faces of said members being inclined from their ends toward the axis of said plunger whereby when said plunger is moved, said strip yieldsgradually, increasing the area of contact with said members from their ends to the axis of said material having straight ends and being loosely carried at its center by said plunger for bridging said contact members when said plunger is moved, the contact faces of said members being inclined from their ends toward the axis of said plunger whereby when said plunger is moved said strip yields and progressively increases the area of contact with said members from their ends to the axis of said' plunger and means for positively limiting the movement of said plunger into contact with said members.

3. A switch for an automobile electric starter comprising a substantially rectangular casing, a sheet metal member forming the top thereof; a pair of spaced stationary contact members secured to the bottom of said casing; an insulating member secured to the bottom of said casing; a plunger; a single yieldable member of conducting material, loosely carried at its center by said plunger and having straight ends for bridging said contact members, when said plunger is moved 'ating with the insulating member in the bottom of said casing to positively limit the movement of the bridging member.

4. A switch for' an automobile electric starter comprising a rectangular sheet metal casing; a sheet metal member forming the top thereof; a pair of spaced stationary contact members secured to the bottom of said casing and extending therethrough; insulating means at either side of the bottom of said casing provided with openings of less dimension than the openings in said casing; a plunger mounted on the top of said casing; a single straight yieldable member of conducting material loosely carried by said plunger for bridging said contact members, when said plunger is moved toward said contact members, the contact faces of said members being inclined from the outer portion toward, the axis of said plunger whereby when said plunger'is depressed said bridging member yields and progressively increases the area of contact with said members from their outer ends to the axis of said plunger;

5. A switch for an automobile electric starter comprising a casing; a pair of terminal contacts on said casing, each having a shank extending therethrough with means on said shank for holding said contact to said casing; said contacts having inclined surfaces: a plunger carrying a single straight yieldable member of conducting material for bridging said contact members, insulating means between said contacts and the bottom of said casing; insulating means separating 

